Yes. Every great technology developed to date has been a net positive for the human race. Including the more controversial ones, like internal combustion engines or nuclear power. Why should AI be different? I think the critics always fixate on the negatives, but ignore the potential big positives.
A common thing is to lump things together like a tech tree. Is it possible to conceive of a world where nuclear power is invented but not nuclear weapons? Combustion engines but not let everyone have a car and then cause cities to be planned around cars?
There are many technologies that have not been a net positive for humanity. Leaded gasoline comes to mind immediately. For many other technologies it is also hard to determine because counterfactuals are hard to reason about.
Even then past performance is not an indicator of future results. Just because you think internal combustion engines were a great invention, doesn't mean AI cannot be bad for humanity.
Long-term, sure. Short-term it is going to cause a lot of suffering.
Depends on your point of view. Has the web been a net positive overall? If your criteria is "instant access to any information" or "catalyze more technological progress" then positive, if your criteria is "young people's mental health" or "how easy it is to control the public's perception about a certain topic" then negative in my opinion. It's all relative.